This research is based on a nationwide study of American Christian church attendance, as reported by churches and denominations. Our database currently has average worship attendances for each of the last 10 years for over 160,000 individual churches throughout the country.

It also uses supplementary information (such as actual membership numbers extrapolated with membership to attendance ratios) to accurately project the attendances of other denominational and independent churches. All told, accurate information is provided for over 295,000 churches.

Division into Evangelical and Mainline Protestant is taken from the Glenmary decadal study of church membership. A list of evangelical denominations can be found at http://www.thearda.com/RCMS/2000/Denoms/evangelical.html; A list of mainline denominations are at http://www.thearda.com/RCMS/2000/Denoms/mainline.html.

This study does not include Christian cults or non-Christian religions in America. Those ‘houses of worship’ would add another 35,000 churches in the United States, making a total of 330,000 houses of worship in America.

The spiritual health of churches is multifaceted, and is obviously much more complex than an attendance trend can portray. However, following the example of St. Luke in the Book of Acts, who used the number of people who showed up at various events as a sign documenting the health and growth of the early church, I would suggest that attendance is the single most helpful indicator of growth, decline and health.

Information has been compiled only for orthodox Christian groups – Protestant, Catholic and Orthodox. The Mormons, Jehovah Witnesses, Unitarian-Universalists and the International Churches of Christ are considered non-orthodox. In addition, information about non-Christian groups has not been compiled.

African American denominations publish very little that is statistical – often not even a list of current churches. An estimate of African American attendance was made for each state (and counties with large African American populations) by correlating the 2000 African American population with the overall 2000 church attendance percentage in the nation (or in the case of southern states, that state’s percentage of population at worship). This study also used African American attendance data from the 1990 Glenmary study and the average attendance at African American churches (from the Barna Research Group).

Independent church data is almost impossible to obtain. (There are actually many fewer totally independent churches than is assumed. Most are part of some voluntary association, which typically keeps some records.) This study has used data from the 1990 & 2000 Glenmary study on Independent charismatic and non-charismatic churches (limited to over 300 in attendance) , and used statistical modeling of similar groups to estimated the number and attendance of independent churches under 300.

United Methodist church numbers include an estimate for children not included in their worship attendance.

In Catholic churches, the definition of what constitutes membership varies with diocese and parish, making numbers sometimes inconsistent from state to state and county to county. Where actual attendance figures were obtainable from the Diocese, those number were used. Where no mass count was done, this study merged membership information from the diocese with mass attendance percentages in other similar dioceses (similar regional and metropolitan / non-metropolitan areas) and applied it to that diocese.

Orthodox Churches are included in Totals, but not included as a separate group because of smallness of size nationwide. Division into Evangelical and Mainline categories is based on the division by the Glenmary Study.